Pair polarizabilities collision-induced light scattering

Several types of collision-induced light scattering spectra are known. We have already mentioned the depolarized translational spectra of rare gas pairs and bigger complexes which arise from the anisotropy of the diatom polarizability. Contrary to the infrared inactivity of like pairs, e.g., Ar-Ar like pairs are Raman active. Furthermore, polarized translational spectra... 

In general, the polarizability is a tensor whose invariants, trace and anisotropy, give rise to polarized and fully depolarized light scattering, respectively. Collision-induced light scattering is caused by the excess polarizability of a collisional pair (or a larger complex of atoms or molecules) that arises from the intermolecular interactions. In Section I.l, we are concerned with the definition, measurement, and computation of interaction-induced polarizabilities and their invariants. 

D. B. DuPre and J. P. McTague. Pair polarizability of hydrogen atoms. Relation to collision induced light scattering and dielectric phenomena in rare gases. J. Chem. Phys., 50 2024-2028 (1969). 

F. Barocchi and M. Zoppi. Collision induced light scattering spectra and pair polarizability of gaseous argon. Phys. Lett. A, 66 99-102 (1978). 

The influence of Van der Waals interactions on the polarizability of interacting molecules manifests itself in deviations from the Clausius-Mosotti equation , in the Kerr effect and in collision induced light scattering . Although measurements of these effects are all performed on bulk systems in thermodynamical equilibrium and not on Van der Waals molecules per se, we will nevertheless say a few words about pair polarizabilities, because, just as in the case of the collision induced IR absorption, much can be learned about Van der Waals interactions from the comparison of experimental and computational results. 

N. Meinander, A. R. Penner, U. Bafile, F. Barocchi, M. Zoppi, D. P. Shelton, and G. C. Tabisz. The spectral profile of the collision induced translational light scattering by gaseous CH4 Determination of the pair polarizability anisotropy. Molec. Phys., 54 493-503 (1985). 

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